TITLE:   GCN CIRCULAR
NUMBER:  32526
SUBJECT: GRB 220907A: Swift detection of a burst
DATE:    22/09/07 14:24:33 GMT
FROM:    Kim Page at U.of Leicester  <kimlpage1978@gmail.com>

K. L. Page (U Leicester), P. A. Evans (U Leicester),
R. A. J. Eyles-Ferris (U Leicester), J.D. Gropp (PSU),
J. A. Kennea (PSU), N. J. Klingler (GSFC/UMBC/CRESSTII),
H. A. Krimm (NSF), N. P. M. Kuin (UCL-MSSL),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL),
B. Sbarufatti (INAF-OAB), M. H. Siegel (PSU),
A. Tohuvavohu (U Toronto) and M. A. Williams (PSU) report on behalf of
the Neil Gehrels Swift Observatory Team:

At 14:05:25 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 220907A (trigger=1123129).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 268.870, -20.315 which is 
   RA(J2000) = 17h 55m 29s
   Dec(J2000) = -20d 18' 54"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a complex peak
structure with a duration of about 20 sec.  The peak count rate
was ~2000 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 14:06:56.5 UT, 90.7 seconds after
the BAT trigger. No source was detected in 188 s of promptly downlinked
data. We are waiting for the full dataset to detect and localise the
XRT counterpart. 

No prompt UVOT data products are available. 

Although there is no counterpart found in the (short) XRT exposure,
the high significance of the BAT detection (8.5 sigma) and the
simultaneous detection by Fermi/GBM (GCN #32525)
indicates that this is an astrophysical event. 

Burst Advocate for this burst is K. L. Page (kimlpage1978 AT gmail.com). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)